Mobile communication antennae can radiate and/or receive in one or more frequency bands, for example in a 900 MHz band, a 1800 MHz band, a 1900 MHz band, or for example in a UMTS band, thus for example in a range from about 1920 MHz to 2170 MHz. In principle there are no restrictions to other frequency ranges.
Proven mobile communication antennae work with radiators or radiator devices which, for example, can transmit and/or receive in two polarisations which are perpendicular to each other. In this respect, X polarisation is also often mentioned, since the two polarisation planes are in principle aligned at a +45° angle and a −45° angle respectively to the horizontal plane or vertical plane. Irrespective of this, the main radiation direction of mobile communication antennae is often set at a radiation angle which differs from a horizontal alignment, and which preferably can be changed by remote control. This involves remotely controllable electronic down-tilt angle adjustment, and an associated adjustment device, often also called an RET unit for short.
Such a controller is to be taken as known, for example, from EP 1 356 539 B1, and an associated method of operating such an RET unit from, for example, EP 1 455 413 B1.
Irrespective of the construction of the antenna systems in the region of a base station, it is necessary that the corresponding antenna systems should be synchronised with each other.
According to most mobile communication standards, the synchronisation of the base station is also ensured via a network and switching system, called “NSS” for short, and also known as the backbone network.
Satellite signals are not required here, since the subscribers are synchronised in the appropriate connection channel. The basic properties of such a mobile communication system are reproduced in, for example, P. Jung: Analyse and Entwurf digitaler Mobilfunksysteme, Verlag Teubner, Stuttgart, 1997, pp. 231-240.
Against this background, the mobile communication network is constantly expanded by providing new mobile communication systems, if appropriate at the same location, in particular at the same mast. This leads to a base station being doubled, tripled etc., i.e. for example to doubling of the number of antennae controlled via the base station and to doubling of the number of HF feed lines extending between the base station and the antenna, and of the associated electronic components, for controlling a system, for example in the form of current-alarmed devices (also sometimes called “CWA devices” for short in the following, the abbreviation “CWA” standing for “current window alarm”). Newer antenna systems are also equipped, for example, with so-called AISG device functions (where AISG stands for “antenna interface standards group”). Antenna systems are also equipped, for example, with 3GPP device functions, which allow communication not via the AISG protocol, but via the 3GPP protocol (where “3GPP” stands for “3rd generation partnership project”).
To achieve a degree of simplification in this case, it is also known, when expanding a mobile communication system by adding a second antenna system and a second base station, to use the feed line between the base station and the antennae jointly as far as possible (feeder sharing). Separate DC supply and current alarm lines to the HF feed lines may still be necessary.
One of the above-mentioned expansions may result in complex or hybrid antenna constructions, as is shown for the prior art in FIG. 1, for example.
In the antenna system according to FIG. 1, known from prior art, three antenna devices, specifically a first antenna device ANT1, a second antenna device ANT2 and a third antenna device ANT3, are mounted for example at a mounting location 1, for example in the form of a mast 1′ (or on a housing or building, etc.) and are provided as mentioned at the outset with suitable radiators, for example X-polarised radiators, to transmit and/or receive in two polarisations.
Three base stations BS1 to BS3 are associated with each of the three antenna devices ANT1 to ANT3.
The base station BS3 may for example be a conventional base station which controls and powers the third antenna device ANT3. In this embodiment, the antenna device is not operated in a manner controlled by a protocol, but using “current alarming”, i.e. using CWA logic and/or CWA devices, which take up different currents depending on fault changes and/or status changes, allowing appropriate control of the components. For this purpose, the third base station BS3 is equipped with the CWA logic and/or CWA control devices, for example via two HF/DC feed lines 5.3a and 5.3b, which are connected to an antenna-side CWA device unit 17.3, which is connected upstream from the associated antenna device ANT3, so that via the HF/DC connecting lines 5.3a and 5.3b, the radiators belonging to the antenna device ANT3 can be controlled correspondingly to operate the antenna system.
The example according to FIG. 1, known from the prior art, may for example be the result of the above-mentioned base station BS3 with the associated antenna arrangement ANT3 and the current-alarmed antenna components 17.3 being expanded with a further antenna system, likewise known from the prior art, with an antenna device ANT1 and an associated base station BS1 as well as an associated mobile communication component 17.1, this added antenna system being equipped for example with ALSG device functions, i.e. it is possible to implement communication between the base station BS1 and the antenna-side mobile communication component 17.1 via the AISG protocol.
In accordance with the example known from the prior art and shown in FIG. 1, a third base station BS2 has additionally been fitted and is for example equipped with 3GPP device functions, which allow communication via the 3GPP protocol. A corresponding interface unit is provided on the base station BS2. Further, the 3GPP control or mobile communication component 17.2 is provided close to the antenna of the associated antenna device ANT2 (i.e. generally at the top of the mast).
To reduce the total number of feed lines 5 required, these may in part be used jointly. In the same embodiment, two further base feed lines 5.1 and 5.2 are provided in addition to the two feed lines 5.3a and 5.3b for the operation of the antenna system ANT3 and are used jointly by the antenna systems ANT1 and ANT2. For this purpose, two diplexers 11 are associated with the two base stations BS1 and BS2, the two output or base feed lines 5.1a and 5.1b or 5.2a and 5.2b respectively also being guided via the two diplexers 11L for the first base station BS1 and the second base station BS2, in such a way that the number of additional feed lines required in this case can be reduced from four to two. Similarly, two diplexers 11H, generally provided on the top of the mast 1′ close to the antenna, must in turn split the two antenna systems ANT1 and ANT2 in order for the HF signals for sending or receiving to be assigned correctly to the individual antenna systems.
Further, FIG. 1 also shows that for example a DC supply and the AISG or 3GPP protocol are provided in each case via one of the base feed lines 5.1a and 5.2a, by the first and second base stations BS1 and BS2 to the respective feed line 5.1 or 5.2 via the respectively associated base-station-side diplexer 11L, and supplied to the mobile communication components 17.1 and 17.2 respectively via the antenna-side diplexer 11H and the subsequent antenna feed lines 5.1′a and 5.2′a. This DC transmission and the transmission of the AISG or 3GPP protocol is shown in dotted lines in FIG. 1, the HF feed line between the base and the antenna basically being shown in thick lines.
FIG. 1 also shows that the two feed lines 5.3a and 5.3b also supply direct current in particular to the current-alarmed devices. This DC transmission is shown in dashed lines in FIG. 1.
The use of the common feed lines 5 may also be further improved and optimised, as is shown for example in FIG. 2 for a further joint antenna system. In this case, two triplexers 111L are now provided on the base station side and are each connected to three terminals on the base station side, a terminal of the two triplexers 111L being connected in each case to a respective terminal of the associated base station BS1, BS2 or BS3. In other words, a first terminal of each of the three base stations BS1 to BS3 is connected to a triplexer 111L and a second terminal of each of the three base stations BS1 to BS3 is connected to an input of the second triplexer 111L. The two triplexers each have a terminal on the antenna side, each of said terminals being connected to one of the two feed lines 5a or 5b. 
On the antenna side, the construction is reproduced approximately symmetrically, the HF signals supplied via the two individual feed lines 5a, 5b now, via two further triplexers 111H, being split correspondingly via the three respective terminals of the two triplexers 111H and being supplied to the three antenna systems ANT1 to ANT3. The three outputs of the first triplexer 111H are thus connected to three inputs of the mobile communication components 17.1, 17.2 and 17.3, the three outputs of the second triplexer 111H being connected to the respective second terminals on the mobile communication components 17.1, 17.2 and 17.3. This means that the two corresponding HF signals are present in each case at the mobile communication components 17.1 to 17.3 and can be transmitted to the first antenna ANT1 via the connection lines 5.1″a, 5.1″b, to the second antenna ANT2 via the connection lines 5.2″a and 5.2″b, and to the third antenna device ANT3 via the two connection lines 5.3″a and 5.3″b. 
In this way, the three antenna systems ANT1 to ANT3 are controlled by means of the AISG and/or 3GPP protocol or via CWA current alarming (without the use of a protocol).
In relation to the antenna system ANT3, so-called bias tee devices BT (i.e. devices for HF-transparent DC coupling and decoupling) are also provided on the base station side and the antenna side in each case, so as to supply the CWA components with direct current on the one hand and, on the other hand, to allow the CWA devices or control components 17.3 provided on the antenna side to take up different currents depending on fault changes and status changes, which can then correspondingly be evaluated at the base station.
In other words, in the antenna systems ANT1 to ANT3, mobile communication components 17, mounted for example on the mast 1′, on a wall 1 of a building etc., are provided, such as TMA amplifiers (so-called low-noise “tower mounted amplifier” reception amplifiers) and/or RET units for remotely adjusting the lowering angle, i.e. the radiation angle of the antennae, also known for short as the down-tilt angle, etc.
Thus, by contrast with FIGS. 1 and 2, it is conceivable to reduce the number of feed lines required in the prior art, possibly for reasons of cost.
In known systems of the type described in relation to FIGS. 1 and 2, the problem would then arise that it is not clear which base station BS1 to BS3 actually supplies a corresponding ALD mobile communication component with direct current (DC voltage). In general, one base station may not provide and/or cover the entire DC supply for all the ALD mobile communication components which are for example associated with another base station.
If different DC supply voltages were provided by a plurality of base stations connected in parallel, then this would also present a problem if the ALD mobile communication components were supposed thus to be supplied by a common HF feed line.
Finally, if there is a further reduction in the feed lines, then older so-called current-alarmed CWA components may also present a further problem in the complexes, i.e. combined mobile communication systems, explained by way of FIG. 1 and FIG. 2 This is because the use of such current-alarmed (CWA) ALD devices or mobile communication components takes up different currents depending on fault changes and/or status changes, and the corresponding base station monitors and must evaluate these currents in order to pass status and fault changes onwards to master systems as a function thereof. The DC interconnection of various ALD mobile communication components via a common feeder, i.e. common feed lines, means that the currents of individual ALD mobile communication components can no longer be divided on the base station side. Thus, correct alarming and/or display of any status changes is no longer provided in an antenna system with CWA systems.
However, in the aforementioned combination of older current-alarmed (CWA) systems and newer systems in which the alarming and/or control takes place for example via the AISG or 3GPP protocol, yet further problems may arise (if these systems are fed via a common feeder construction). This leads under some circumstances to incompatibilities with a common feed line, specifically if different protocols, used independently of one another (different primaries) are used. In other words, data collisions may occur on the data bus and do not allow correct operation of the antenna system as a whole in the context of a mixed antenna construction of the type described. In particular, it is possible for example that AISG or 3GPP protocol signals or any additional client-specific protocols may be short-circuited by CWA-ALD components (differently depending on the various current-alarmed ALD components), and this can lead to correct data communication breaking down completely.
The object of this invention is therefore to create an improved complex antenna system, along with the central transmission and control devices required therefor, which allows the operation of a plurality of individual antenna systems with associated base stations (i.e. for transmitting different frequency bands) in a “mixed” environment, using different components.
The solution according to the invention is based on a multiplexer (MUX), i.e. a multiplex circuit, which will also sometimes be referred to as MUX for short in the following, being used in each case, on the base station side and moreover on the antenna side.
This is a so-called “intelligent” multiplexer circuit, which may be constructed in the form of a diplexer or triplexer or thus generally in the form of a multiplexer, depending on how many base stations and associated antenna devices are to be used jointly exploiting a common feeder construction (common feed line construction).
The multiplex construction on the base station side thus scans, on the terminal side associated with the base stations, for whether the relevant base station for example transmits one or more AISG protocols, one or more 3GPP protocols and/or possibly only one or more direct current signals (DC signals) without a corresponding protocol, in the last of which cases this would then be current-alarmed (CWA) device control or optionally device control which is provided merely by communication by the antenna-side mobile communication components from these to the base station (it also being possible alternatively or additionally to have device control in which the communication between the antenna-side mobile communication components and the base station is for example initiated and carried out by the base station). The corresponding scanning result is then transmitted to the antenna devices, i.e. to the multiplex circuits on the antenna side connected upstream from the antenna devices, via the common feeder construction using a suitable protocol. This results in turn in an echo (return transmission), for example to an AISG protocol or a 3GPP protocol or the provision of a pure DC signal, as if the relevant base station had transmitted an AISG protocol and a 3GPP protocol or any other protocol (for example a proprietary protocol) on separate paths or if corresponding antenna control took place only via current-alarmed devices (CWA), or devices which communicate only from the antenna side to the base station side. In other words, the protocols exchanged and/or transmitted between the base-station-side and antenna-side multiplex circuit are supplied to the corresponding antenna devices or base stations with the correct assignment.
The multiplexer circuit on the antenna side checks whether loads are connected to the antenna-side outputs thereof and optionally measures the current uptake thereof and communicates this result to the base-station-side multiplex circuit. Thus, it is also possible correspondingly to provide a DC supply of any size, such as would be fed into an HF feed line when using an older base station at the relevant point, for the CWA devices in a precise manner.
This means that the respective direct current required can be adjusted precisely and a corresponding DC supply of the associated antenna units can be simulated at the base-station-side terminals of the base-station-side multiplexer circuit.
Finally, within the scope of the invention, different DC voltage sources can be interconnected at the base stations, in which case a galvanic separation between the base-station side terminals of the multiplexer is produced by the antenna-side terminals of the multiplexer. This makes it possible for the base-station-side multiplexer to simulate, at the corresponding inputs provided for the connection to the base station, power uptakes which correspond to the states (for example the corresponding power uptake in an operation or fault state) at the ALD components associated with the respective base station (with a fixed setting or fully configurable).
In a preferred embodiment of the invention, a further separate interface, which can be used either to control the multiplexer and/or an antenna device which can be reached via it and/or to provide direct current, is provided on the relevant multiplexer.
This mentioned additional interface on the multiplexer can also be omitted in the case of sufficient total DC power at the base-station-side terminals.